This relates to more efficient delivery of power through a power-enabled communications port.
A number of different data communications standards allow devices, such as personal computers, to provide power to peripheral devices via data connections. As just two examples, the Universal Serial Bus (“USB”) and IEEE1394 (“FireWire”) standards provide power as well as data connectivity. As a result of the availability of power from these types of data ports, an ever-increasing variety of devices are becoming available that draw their power from such a power-enabled data port.
While originally all such devices were computer peripheral-type devices such as, for example, network adapters, printers or storage devices, an increasing number of such devices are not data devices at all or have only minimal data functions. For example, mobile telephones can be connected via such ports to a computer for the purpose of transferring data files (e.g., photographs taken with the telephone's camera), but the telephone also can be charged using that connection. Many users find it more convenient to charge their mobile telephones via the data connection even though they may have no data to transfer. As a further example, one available type of a device with absolutely no data functions is a warming plate for a coffee mug, designed to be powered from a USB port.
The standards for power-enabled communications ports specify how much power or current must be available from an individual port. For example, the USB standard provides a maximum of 500 mA of current at 5 V. As devices are introduced that demand more and more power, the standards must continually be upgraded.